Association of Total Small Bowel Length with Glycaemic Control and Metabolic Syndrome in Metabolic and Bariatric Surgery Patients: A Cross-Sectional Study in a Taiwanese Cohort

Abstract The small intestine plays a vital role in nutrient absorption, hormone regulation, and glucose metabolism, and its anatomical variability may contribute to differences in metabolic outcomes. While the length of the total small bowel (TSBL) has been recognized to vary significantly between individuals, its potential metabolic implications, especially in the context of glycaemic control and metabolic syndrome, remain under-investigated. In the setting of metabolic and bariatric surgery (MBS), where metabolic improvements are often dramatic, understanding the anatomical contributions to these outcomes could enhance patient stratification and procedural planning. Prior studies have suggested associations between small bowel length and body height, but limited research has examined its relationship with biochemical parameters such as glycated haemoglobin (HbA1c) and the broader constellation of metabolic syndrome features. This study aimed to assess the relationship between TSBL and key glycaemic parameters, particularly HbA1c levels, as well as the presence of metabolic syndrome, in patients undergoing primary bariatric bypass surgery. We conducted a comprehensive cross-sectional analysis in a high-volume bariatric center in Taiwan, applying standardized bowel length measurements and rigorous exclusion criteria to minimize confounding factors such as medication use and renal dysfunction. Through a combination of univariate and multivariate regression analyses, the study sought to determine whether anatomical length variations of the small bowel could be linked to measurable differences in metabolic profiles, independent of traditional anthropometric indicators like body mass index (BMI).